Modeling effects of traffic and landscape characteristics on ambient nitrogen dioxide levels in Connecticut

An integrated exposure model was developed that estimates nitrogen dioxide (NO(2)) concentration at residences using geographic information systems (GIS) and variables derived within residential buffers representing traffic volume and landscape characteristics including land use, population density and elevation. Multiple measurements of NO(2) taken outside of 985 residences in Connecticut were used to develop the model. A second set of 120 outdoor NO(2) measurements as well as cross-validation were used to validate the model. The model suggests that approximately 67% of the variation in NO(2) levels can be explained by: traffic and land use primarily within 2 km of a residence; population density; elevation; and time of year. Potential benefits of this model for health effects research include improved spatial estimations of traffic-related pollutant exposure and reduced need for extensive pollutant measurements. The model, which could be calibrated and applied in areas other than Connecticut, has importance as a tool for exposure estimation in epidemiological studies of traffic-related air pollution.     

Relationship between Sulfate Aerosol and Visibility

A PM₁₀ monitoring network was established throughout the South Coast Air Basin (SOCAB) in the greater Los Angeles region during the calendar year 1986. Annual average PM₁₀ mass concentrations within the Los Angeles metropolitan area ranged from 47.0 µg m^-3 along the coast to 87.4 µg m^-3 at Rubldoux, the furthest inland monitoring station. Measurements made at San Nicolas Island suggest that regional background aerosol contributes between 28 to 44 percent of the PM₁₀ aerosol at monitoring sites In the SOCAB over the long term average. Five major aerosol components (carbonaceous material, NO^- ₃, SO⁼ ₄, NH⁺ ₄, and soil-related material) account for greater than 80 percent of the annual average PM₁₀ mass at all on-land monitoring stations. Peak 24-h average mass concentrations of nearly 300 µg m^-3 were observed at inland locations, with lower peak values (?130–150 µg m^-3) measured along the coast. Peak-day aerosol composition was characterized by increased NO^- ₃ Ion and associated ammonium ion levels, as compared to the annual average. There appears to be only a weak dependence of PM₁₀ mass concentration on season of the year. This lack of a pronounced seasonal dependence results from the complex and contradictory seasonal variations in the major chemical components (carbonaceous material, nitrate, sulfate, ammonium ion and crustal material). At most sites within the Los Angeles metropolitan area, PM₁₀ mass concentrations exceeded both the annual and 24-h average federal and state of California PM₁₀ regulatory standards.     

PERFORMANCE AND PERSISTENCE OF GREEN FLUORESCENT PROTEIN （gfp） MARKED AZOTOBACTER CHROOCOCCUM IN STERILIZED AND UNSTERILIZED WHEAT RHIZOSPHERIC SOIL

ThepracticaluseofAzotobacterchroococcumasbiofertilizer hasbeenincreasinglyidentifiedinrecentyears.Oftentheefficacy ofthesebacteriaisassessedonthebasisofcropresponseswithout knowingthesurvival,persistenceandcompetitiveabilityofthein troducedstrain.Inoculat…     

Estimates of health benefits due to reductions in ambient NO2 levels

A method is presented here by which the actual numbers of individuals in the U.S. population who would be expected to suffer respiratory illness as a result of exposure to ambient nitrogen dioxide (NO₂) concentrations in excess of the Federally-designated ambient air quality standard can be estimated. At the same time we have attempted to quantify how these adverse health effects would be alleviated by various degrees of reductions in current ambient concentrations. In addition, the health benefit expected to be derived by various NO_x emission control strategies will be examined utilizing the health benefit estimation method presented.It is estimated that there were approximately 33.2×10⁶ excess cases of respiratory illnesses in the U.S. in 1973 associated with ambient NO₂ concentrations in excess of the national ambient standard. A reduction of approximately 50 to 60 percent below 1973 NO₂ levels is needed to essentially eliminate excess respiratory illness associated with ambient NO₂ concentration.     

Health benefits due to reductions of CO levels

A method is presented by which an upper limit of the adverse health effect of existing ambient CO concentrations on the U. S. population can be estimated. The method is based upon estimating the primary human physiological response to CO concentrations (COHb%) for the population in terms of person-hour-COHb>1.5% resulting from the time exposure of the population to CO concentrations in excess of the federally designated ambient air quality standard. The estimates of person-hour-COHb>1.5% are for exposures only to ambient CO concentrations and do not take into account the additional CO exposure for people who smoke or have occupational exposures.We estimate that there were up to 30.9×10⁹ person-hour-COHb>1.5% in 1973 due to ambient concentrations in excess of the ambient 8-hour CO standard, with approximately 5×10⁹ person-hour-COHb>1.5% occurring West of the Continental Divide and 25.9>10⁹ person-hour-COHb>1.5% occuring East of the Continental Divide; of these 21.3×10⁹ personhour-COHb>1.5% occurred in New York City. It was also estimated that a 60% reduction in 1973 ambient concentrations of CO (corresponding to an automotive emmision standard of less than 15 g/mile) would be needed to reduce to zero the person-hour-COHb>1.5%. The maximum estimated effects on the U.S. population of increases in ambient CO concentration above 1973 levels are also presented.     

Spatiotemporal calibration of atmospheric nitrogen dioxide concentration estimates from an air quality model for Connecticut

Environmental and Ecological Statistics - A spatiotemporal calibration and resolution refinement model was fitted to calibrate nitrogen dioxide ($$\hbox {NO}_2$$) concentration estimates from the...     

Ventilation requirements in occupied spaces during smoking and nonsmoking occupancy

Ventilation requirements in occupied spaces have traditionally derived largely from odor control. The requirements have rested on the notion that an environment that seems subjectively acceptable to a visitor will in fact be healthful and comfortable for both visitor and occupant alike. Ventilation requirements have derived secondarily from criterion concentrations of notable contaminants (e.g., carbon dioxide). The present investigation looked again at both sensory (odor, irritation) and physical criteria of acceptability, paying particular attention to the difference between smoking and nonsmoking occupancy in a well-controlled environmental chamber. More than 200 persons (visitors) made judgments of odor intensity and acceptability under various conditions of occupancy (up to 12 nonsmoking occupants; a temperature of up to 25.5°C; up to 16 cigarettes smoked per hour). The results implied that under nonsmoking conditions and moderate humidity only about 7.5 cfm (3.8 L sec⁻¹) of fresh air per occupant sufficed to satisfy visitors, but that under smoking conditions at least 5 times as much fresh air is necessary. Our estimate of ventilation requirements for smoking were derived in part from measurements of carbon monoxide and total suspended particulate (TSP) mass concentration. Levels of TSP achieved during realistic smoking and ventilation rates exceeded levels deemed acceptable outdoors. Surfaces in the chamber played an important role in the elimination of particles, presumably via adsorption. Use of an electrostatic precipitator could keep TSP levels under control. Nevertheless, it remains to be seen whether control of TSP will eliminate the need for enormous ventilation for odor control during smoking occupancy.     

Fly ash bricks development using concrete waste debris and self-healing bacteria

Journal of Material Cycles and Waste Management - In this study, an effort has been made to use concrete waste debris for the manufacturing of fly ash bricks as a sustainable material. Though in...